// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2014 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_CWISE_BINARY_OP_H
#define EIGEN_CWISE_BINARY_OP_H

namespace Eigen {

namespace internal {
    template <typename BinaryOp, typename Lhs, typename Rhs> struct traits<CwiseBinaryOp<BinaryOp, Lhs, Rhs>>
    {
        // we must not inherit from traits<Lhs> since it has
        // the potential to cause problems with MSVC
        typedef typename remove_all<Lhs>::type Ancestor;
        typedef typename traits<Ancestor>::XprKind XprKind;
        enum
        {
            RowsAtCompileTime = traits<Ancestor>::RowsAtCompileTime,
            ColsAtCompileTime = traits<Ancestor>::ColsAtCompileTime,
            MaxRowsAtCompileTime = traits<Ancestor>::MaxRowsAtCompileTime,
            MaxColsAtCompileTime = traits<Ancestor>::MaxColsAtCompileTime
        };

        // even though we require Lhs and Rhs to have the same scalar type (see CwiseBinaryOp constructor),
        // we still want to handle the case when the result type is different.
        typedef typename result_of<BinaryOp(const typename Lhs::Scalar&, const typename Rhs::Scalar&)>::type Scalar;
        typedef typename cwise_promote_storage_type<typename traits<Lhs>::StorageKind, typename traits<Rhs>::StorageKind, BinaryOp>::ret StorageKind;
        typedef typename promote_index_type<typename traits<Lhs>::StorageIndex, typename traits<Rhs>::StorageIndex>::type StorageIndex;
        typedef typename Lhs::Nested LhsNested;
        typedef typename Rhs::Nested RhsNested;
        typedef typename remove_reference<LhsNested>::type _LhsNested;
        typedef typename remove_reference<RhsNested>::type _RhsNested;
        enum
        {
            Flags = cwise_promote_storage_order<typename traits<Lhs>::StorageKind,
                                                typename traits<Rhs>::StorageKind,
                                                _LhsNested::Flags & RowMajorBit,
                                                _RhsNested::Flags & RowMajorBit>::value
        };
    };
}  // end namespace internal

template <typename BinaryOp, typename Lhs, typename Rhs, typename StorageKind> class CwiseBinaryOpImpl;

/** \class CwiseBinaryOp
  * \ingroup Core_Module
  *
  * \brief Generic expression where a coefficient-wise binary operator is applied to two expressions
  *
  * \tparam BinaryOp template functor implementing the operator
  * \tparam LhsType the type of the left-hand side
  * \tparam RhsType the type of the right-hand side
  *
  * This class represents an expression  where a coefficient-wise binary operator is applied to two expressions.
  * It is the return type of binary operators, by which we mean only those binary operators where
  * both the left-hand side and the right-hand side are Eigen expressions.
  * For example, the return type of matrix1+matrix2 is a CwiseBinaryOp.
  *
  * Most of the time, this is the only way that it is used, so you typically don't have to name
  * CwiseBinaryOp types explicitly.
  *
  * \sa MatrixBase::binaryExpr(const MatrixBase<OtherDerived> &,const CustomBinaryOp &) const, class CwiseUnaryOp, class CwiseNullaryOp
  */
template <typename BinaryOp, typename LhsType, typename RhsType>
class CwiseBinaryOp : public CwiseBinaryOpImpl<BinaryOp,
                                               LhsType,
                                               RhsType,
                                               typename internal::cwise_promote_storage_type<typename internal::traits<LhsType>::StorageKind,
                                                                                             typename internal::traits<RhsType>::StorageKind,
                                                                                             BinaryOp>::ret>,
                      internal::no_assignment_operator
{
public:
    typedef typename internal::remove_all<BinaryOp>::type Functor;
    typedef typename internal::remove_all<LhsType>::type Lhs;
    typedef typename internal::remove_all<RhsType>::type Rhs;

    typedef typename CwiseBinaryOpImpl<BinaryOp,
                                       LhsType,
                                       RhsType,
                                       typename internal::cwise_promote_storage_type<typename internal::traits<LhsType>::StorageKind,
                                                                                     typename internal::traits<Rhs>::StorageKind,
                                                                                     BinaryOp>::ret>::Base Base;
    EIGEN_GENERIC_PUBLIC_INTERFACE(CwiseBinaryOp)

    typedef typename internal::ref_selector<LhsType>::type LhsNested;
    typedef typename internal::ref_selector<RhsType>::type RhsNested;
    typedef typename internal::remove_reference<LhsNested>::type _LhsNested;
    typedef typename internal::remove_reference<RhsNested>::type _RhsNested;

#if EIGEN_COMP_MSVC && EIGEN_HAS_CXX11
    //Required for Visual Studio or the Copy constructor will probably not get inlined!
    EIGEN_STRONG_INLINE
    CwiseBinaryOp(const CwiseBinaryOp<BinaryOp, LhsType, RhsType>&) = default;
#endif

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE CwiseBinaryOp(const Lhs& aLhs, const Rhs& aRhs, const BinaryOp& func = BinaryOp())
        : m_lhs(aLhs), m_rhs(aRhs), m_functor(func)
    {
        EIGEN_CHECK_BINARY_COMPATIBILIY(BinaryOp, typename Lhs::Scalar, typename Rhs::Scalar);
        // require the sizes to match
        EIGEN_STATIC_ASSERT_SAME_MATRIX_SIZE(Lhs, Rhs)
        eigen_assert(aLhs.rows() == aRhs.rows() && aLhs.cols() == aRhs.cols());
    }

    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR Index rows() const EIGEN_NOEXCEPT
    {
        // return the fixed size type if available to enable compile time optimizations
        return internal::traits<typename internal::remove_all<LhsNested>::type>::RowsAtCompileTime == Dynamic ? m_rhs.rows() : m_lhs.rows();
    }
    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR Index cols() const EIGEN_NOEXCEPT
    {
        // return the fixed size type if available to enable compile time optimizations
        return internal::traits<typename internal::remove_all<LhsNested>::type>::ColsAtCompileTime == Dynamic ? m_rhs.cols() : m_lhs.cols();
    }

    /** \returns the left hand side nested expression */
    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const _LhsNested& lhs() const { return m_lhs; }
    /** \returns the right hand side nested expression */
    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const _RhsNested& rhs() const { return m_rhs; }
    /** \returns the functor representing the binary operation */
    EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const BinaryOp& functor() const { return m_functor; }

protected:
    LhsNested m_lhs;
    RhsNested m_rhs;
    const BinaryOp m_functor;
};

// Generic API dispatcher
template <typename BinaryOp, typename Lhs, typename Rhs, typename StorageKind>
class CwiseBinaryOpImpl : public internal::generic_xpr_base<CwiseBinaryOp<BinaryOp, Lhs, Rhs>>::type
{
public:
    typedef typename internal::generic_xpr_base<CwiseBinaryOp<BinaryOp, Lhs, Rhs>>::type Base;
};

/** replaces \c *this by \c *this - \a other.
  *
  * \returns a reference to \c *this
  */
template <typename Derived>
template <typename OtherDerived>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Derived& MatrixBase<Derived>::operator-=(const MatrixBase<OtherDerived>& other)
{
    call_assignment(derived(), other.derived(), internal::sub_assign_op<Scalar, typename OtherDerived::Scalar>());
    return derived();
}

/** replaces \c *this by \c *this + \a other.
  *
  * \returns a reference to \c *this
  */
template <typename Derived>
template <typename OtherDerived>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Derived& MatrixBase<Derived>::operator+=(const MatrixBase<OtherDerived>& other)
{
    call_assignment(derived(), other.derived(), internal::add_assign_op<Scalar, typename OtherDerived::Scalar>());
    return derived();
}

}  // end namespace Eigen

#endif  // EIGEN_CWISE_BINARY_OP_H
